I will review results in the literature that suggest that neocortical pyramidal cells should have three separate computational zones:

1) soma and proximal dendrites
2) distal dendrites
3) apical tuft

The reason why this level of detail is needed is that each of these zones differ significantly in several key properties:

i) impact of individual EPSPs
ii) synaptic plasticity rule
iii) cell type providing inhibition

As a result of these major differences, each of these three zones carry out distinct computations.  While these ideas are more speculative, I will broach discussion of the following computational themes:

1. Proximal dendrites
  • integrate-and-fire
  • E/I balance
  • learning temporal sequences

2. Distal dendrites 
  • local NMDA spikes
  • learns sensory invariances

3. Apical Tuft
  • controls gain of somatic transfer function
  • learns new “context” for pyramidal cells’s function
  • possibly also: suppression of predicted information
  • possibly also: implementation of backpropagation rule

Also, I will propose two short modelling projects to explore the computations in: 1) proximal dendrites; 2) distal dendrites.